Electrosurgical instruments have become widely used by surgeons in recent years. Most electrosurgical instruments include a hand-held instrument, or pencil, which transfers radio-frequency (RF) electrical energy (electrical current) to a tissue site. The electrical current may be returned to the source via a return electrode pad positioned under a patient (typically monopolar use), or a smaller return electrode positioned in bodily contact with or immediately adjacent to the surgical site (typically bipolar use). The waveforms which result from the RF electrical current may be used to produce a variety of effects, depending on the power applied, and the frequency used. These effects include surgical cutting, coagulation, and cauterizing (or sealing), by application of electric current to biological tissue. The current is produced by radio-frequency electrical energy generated from an appropriate electrosurgical generator.
These useful effects are produced during surgery by “electrosurgical pencils,” surgical instruments which have a hand piece, to which is attached an active electrode. The main body of the hand piece for most electrosurgical pencils is comprised of a molded plastic hand piece, within which resides a second plastic holder, for positioning and holding appropriate electrical circuitry, which acts as a conduit for electrical current, and a switch (or switches) by which the current may be controlled. The active electrode, at the distal end of the electrosurgical pencil, is, by such switch or switches, electrically connected, through the electrical circuitry within the interior plastic holder, to a suitable RF source of electrical current (i.e., an electrosurgical generator, or “generator”) which produces the radio-frequency electrical energy necessary for the operation of the electrosurgical pencil.
In general, when a monopolar procedure is performed on a patient with an electrosurgical pencil, electrical energy from the generator is conducted through the active electrode to the tissue at the site of the operation and then through the patient to a return electrode. The return electrode is typically placed at a convenient place on the patient's body and is attached to the generator by a conductive material. The active electrode is an electrically conducting element which comes in a variety of forms, so that the surgeon may apply the electrical energy from the electrosurgical pencil in a variety of ways.
When a bipolar procedure is performed on a patient with an electrosurgical pencil, electrical energy from the generator is conducted through and active electrode to the tissue at the site of the operation, and then through the patient tissue to a return electrode. The return electrode in such case is proximal to the active electrode, typically within millimeters distance, and provides a return path to the generator, alleviating the need for a separate return pad electrode as used in monopolar procedures.
The electrosurgical pencils already in use may be operated by a handswitch or a foot switch. However, hand switching on the hand piece of the electrosurgical pencil has become the standard method for changing the electrical current from that suitable for surgical cutting, to coagulation and cauterizing, and back to cutting. Typically, electrosurgical instrument systems allow the surgeon to change between two pre-configured settings (i.e., coagulation and cutting) via two discrete buttons disposed on the exterior of the electrosurgical pencil (external “Buttons”). Such Buttons, when pressed, generally activate another conductive or non-conductive component, which then activates the conductive switching elements of the electrosurgical pencil, thereby allowing current to flow through the electrosurgical pencil to the active electrode. Other switching arrangements have been developed, including three button systems and rocker arm systems, depending on the number of functions which are desired, and the surgeon's preferred switching “feel” and activation method.
Regardless of the switch type and number of settings, many switches for electrosurgical pencils presently in use utilize suitably sized, stamped, metal to form the electrical circuitry which carries current from the electrical generator leads, through one or more electrical conductors (or conducting strips), to the active electrode. Other switches for electrosurgical pencil include the use of small printed circuit boards (“PCBs”), with attached conductors, dome switches, and various connectors. Once a switch has been assembled, it may then be incorporated as a sub-assembly into the hand piece of an electrosurgical pencil.
Examples of such stamped electrical circuitry may be found in U.S. Pat. Nos. 5,376,089 and 4,427,006. U.S. Pat. No. 5,376,089 shows an invention in which the circuitry of the electrosurgical pencil switch is stamped in a single piece, to form the totality of the switching circuitry, and then stamped again at a number of “punch points,” to electrically isolate each of the conducting strips of the switch after the conducting strips are positioned and secured within a housing. After securing the conducting strips, the switch sub-assembly is then assembled within the housing of an electrosurgical pencil.
One benefit of stamping switch circuitry in a single piece is ease of manufacture, as stamping all the circuitry in a single piece avoids wiring by hand in a “bread board” fashion, with conducting wire and solder. Another benefit of stamping switch circuitry is the creation, with one single stamping, of all electrical conducting strips necessary to conduct current from generator leads to active electrode. At the same time, the stamping operation may be used to create electrical spring contacts, as in U.S. Pat. No. 5,376,089, or “cantilevered conductor strips,” as in U.S. Pat. No. 4,427,006 (collectively, these may be termed “Spring Contacts”). The Spring Contacts generally provide the resistive mechanism necessary to break electrical contact between the generator leads and the active electrode. In operation, the Spring Contacts may flex, to make electrical contact between the otherwise electrically isolated electrical strips of the electrosurgical pencil switch circuitry. Flexing of the Spring Contacts occurs when buttons which may be reached and activated from the exterior of the electrosurgical pencil hand piece are pressed. As resilient pieces, however, the Spring Contacts may also return to their original positions, or move partially to their original positions, to break electrical contact, and thereby again electrically isolate the electrical strips of the electrosurgical pencil switch circuitry. This occurs when pressure on the accessible exterior buttons is reduced.
The largest single problem with most common switching arrangements is that, while the electrosurgical pencil switch circuitry as a whole may be stamped in a single piece, the conducting strips of the circuitry must be stamped again at the “punch points” to electrically isolate each of the conducting strips. This second, punch point, stamping generally takes place before the conducting strips of the electrosurgical pencil switch circuitry are fastened in place within the molded insulative holding and positioning body of the hand piece of the electrosurgical pencil. As a result, the conducting strips of the electrosurgical pencil switch circuitry, or other necessary electrical components such as “dome switches,” must be located by human eyes, selected with human thought, and touched by human hands. Hand labor, in fact, is often necessary, depending on the arrangement utilized, to locate the correct electrical component for loading into the molded insulative holding and positioning body, positioning such components within that body, or fastening such components in place. As the electrical components of electrosurgical pencil switches are small, such work by humans is slow, sometimes inaccurate, and often requires special tools or fasteners.
In a small number of switching arrangements where the circuitry is stamped in a single piece, the conducting strips of the circuitry may be stamped at the punch points to electrically isolate each of the conducting strips after the conducting strips are fastened in place within the molded insulative holding body of the hand piece. This kind of manufacture, which may be seen in U.S. Pat. No. 5,376,089, allows the elimination of some human handling of small switch parts, however some assembly by hand is still necessary even in the invention of this patent, as the dome shaped members which make contact with underlying Spring Contacts must be positioned after the molded insulative holding body of the hand piece is assembled, and sealing tape is placed such dome shaped members. As a result, the conducting some conductive and non-conductive components of all electrosurgical pencil switches presently must still be located, selected, and positioned by human hands.
As electrosurgical pencils are, even when assembled by humans, relatively small and simple devices, and used by medical professionals under circumstances which benefit from a “disposable” tool, electrosurgical pencils have become less expensive to produce. However, like most manufactured items, and all medical tools (especially inexpensive medical tools), the distribution of electrosurgical pencil adds greatly to their overall cost to the surgical profession and, ultimately, to their patients and health care costs. What is needed, then, is an even less resource intensive method of manufacturing electrosurgical pencils, particularly at the stage where the electrosurgical pencil switch circuitry is loaded into the molded insulative holding and positioning body of the electrosurgical pencil hand piece.
The Switch of the Pencil of the present invention reduces the cost of manufacture of electrosurgical pencil by eliminating human selection and handling during the assembly of electrosurgical pencil switches and hand pieces. The design of the Switch allows this through an innovative design in the Switch circuitry and other electrical components, which allows 100% machine assembly (i.e., the assembly of the Switch and Cabinet of the hand piece is entirely automated), and by use of otherwise common components. The present invention thereby overcomes the cost drawbacks of prior devices, saving significant manufacturing costs, which results in the saving of dollars of unnecessary cost to the surgeon, and tens of dollars of extra cost to the patient or her insurer.
The Switch of the Pencil of the present invention also allows use of commonly available, inexpensive, and standardized “snap dome springs.” The Dome Springs, which may be of formed from different materials and different thicknesses, provide a variety of electrical contact closing forces. The Dome Springs therefore provide a variety of pressures and “actions” when depressing or releasing the exterior activation buttons of the Pencil during use. This is important, as individual surgeons, having individual strengths and preferences, wish to select the tactile feel of the tool they will use while undertaking the delicate tasks of cutting and cauterizing.
No patent or electrosurgical pencil of which the inventor is aware allows automation of the assembly of the electrosurgical pencil hand piece, to reduce costs, and free up direct human attention and effort, and no electrosurgical pencil of which the inventor is aware allows the surgeon to so finely select the tactile feel of her electrosurgical pencil by selecting activation button pressure and action in a electrosurgical pencil costing so little.